The present invention relates to a method and system for processing a photographic film and in particular to a method and system for processing a photographic film that enables optimisation of images obtained from the film. The invention also relates to a camera that enables optimisation of captured images.
The ISO rating of a film defines the speed of the film, which allows the camera or photographer to choose a combination of aperture and shutter speed to give optimum exposure. In conventional camera systems, the ISO rating of the film used in the camera is conveyed to the camera via DX coding or other suitable means, such as in the APS system or manually set by the photographer. This is done in anticipation that the film will be processed in a standard process such as the Kodak C41 industry standard process or an equivalent having a specified development time. Processing systems running such processes are fixed in development time by a combination of path-length through the developer tank of the processing system and transport speed of the film as it passes through the developer tank.
Novel processing systems have been developed which use a single tank and batch chemistry rather than tank chemistry, with removal of spent chemicals prior to injection into the processor of the subsequent chemistry stage. The system disclosed in U.S. Patent Application Publication No. 2002/0061195, published May 23, 2002 in the name of Eastman Kodak Company, is an example of such a processing system. This system uses a cylindrical rotating tank in which a roller urges a wave of chemicals over the surface of a film being processed as the cylindrical tank rotates. The development time in such a processing system is not fixed like the development time in tank processors. Indeed, the development time can vary substantially and is controlled by software, which decides when to remove developer and replace it with the next chemistry, such as a bleaching agent. U.S. Pat. No. 5,323,204 discloses an exposure control apparatus and various accompanying methods for improving the overall quality of photographic images. The quality improvement is attained through user selection of a desired display size and/or focal length photographing mode for each image to be captured followed by an optimisation, for that size and mode, of various photographic parameters.
A problem exists in that sometimes a camera is used in situations when a different ISO rating would be preferable to the one that the film in use in the camera has been designed for. In such situations it is desirable to use a different ISO rating setting to capture an image, but if this is done, when the film is processed using a conventional processing method and system, the processing is not optimised and image quality is degraded.
A method and system is required that enables the image quality of output images from the system to be optimised.
A camera is also required that provides a user with the ability to select an ISO rating setting for use with a film to ensure optimisation of captured images without adversely affecting the quality of the processed images obtained from the film.
According to a first aspect of the present invention, there is provided a camera adapted to couple data such as magnetic information to a film in use in the camera, the data relating to an ISO rating setting for the whole film or the ISO rating setting for a particular image captured by the camera.
Preferably, the camera further comprises user operable selection means to enable a user to select a desired ISO rating setting for the film.
More preferably, the user operable selection means comprises a dial arranged on the camera-casing, selectively rotatable between a plurality of predetermined positions each of the positions corresponding to a predetermined ISO rating setting. Any other suitable user operable selection means could also be used. For example, a Liquid Crystal Display arranged on the camera casing in combination with a toggle switch could be used.
According to a second aspect of the present invention there is provided a photographic processing system comprising reading means to identify from magnetic information stored on a film to be processed the ISO rating setting at which images on the film were captured.
The system includes a developer stage to receive the film to be developed and a control unit to select a development time for the film in dependence on the identified ISO rating setting. The reading means includes a magnetic detector to read the magnetic information stored on the film and provide an identification signal indicative of the ISO rating setting used for the film to the control unit.
Preferably, the control unit comprises a microprocessor. In one example, the microprocessor is arranged to receive the identification signal indicative of the ISO rating setting used for the film and/or individual exposures (captured images) and retrieve an appropriate development time from a look-up table of stored development time values.
Preferably, the processing system is a single-chamber processing system in which the control unit is arranged to control the system such that, in use, after the development time elapses, the developer is removed from the processing chamber and a subsequent processing fluid, such as a bleaching agent, is provided to said chamber.
According to a third aspect of the present invention, there is provided a method of photographic processing, comprising the step of identifying an ISO rating setting used for a film to be processed from stored data, such as magnetically stored data, on the film. The film is provided to a developer stage of a photographic processing system. The development time for the film is controlled, automatically in dependence on the identified ISO rating setting used for the film or individual exposures within the film.
Preferably, the step of identifying an ISO rating setting used for a film to be processed comprises the steps of identifying an ISO rating setting used for each image captured on the film and calculating an average ISO rating setting for the film in dependence on the ISO rating setting identified for each of the captured images.
Preferably, the method further comprises, after the film has been developed the steps of, digitally scanning the developed film and printing an output image.
More preferably, the process image quality is further enhanced through knowledge of film type, identified ISO rating setting and process (e.g. development) time used. Algorithms used to adjust digital file data for contrast, brightness and colour factors may include terms to take into account the variations in these factors resulting from variation in the process (development) time given to images which have been exposed in a known variation from the normal exposure. Calculations are performed with the algorithms to optimise image quality. The calculation occurs, preferably, within an output (e.g. printing) device associated with the digital scanning operation.
In an alternative example, scanning of individual images may be optimized in similar flexible mode according to the information, magnetically stored during image capture.
The invention provides a camera that is adapted to allow a user to select and set a required ISO rating setting for each film or each image captured. This in turn ensures that when the film is developed in a photographic processing system, the quality of output images may be optimised. In particular, by allowing a user to vary the ISO rating setting of a captured image and also ensuring that this information is stored and used during development, a customised development time can be selected automatically for each film processed, and optimised printing is provided. This ensures that the maximum possible image quality is obtained for the output images obtained from the developed film.